±500 kV高压直流XLPE电缆温度分布及其影响因素研究

Study on Temperature Distribution of ±500 kV HVDC XLPE Cable and Its Influencing Factors

温度分布是直流电缆运维检修的重要参数之一。由于高压直流输电起步较晚,高压直流电缆的研究不如交流电缆丰富、深入,因此对其温度分布影响因素的研究具有重要意义。通过Comsol有限元软件建立二维对称模型,计算±500 kV高压直流XLPE电缆稳态运行时的温度分布,求出适合电缆长期运行的载流量,并从载流量和环境温度两方面研究温度分布变化。仿真结果表明:载流量对温度分布变化具有较大的影响,当环境温度高于15℃时,导体温度约束载流量大小,环境温度低于15℃时,绝缘层最大允许温差约束载流量大小。最后通过实验验证了仿真的正确性。

Temperature distribution is one of the important parameters of DC cable in operation and maintenance.Due to the late start of HVDC transmission,the research on HVDC cable is not as rich and deep as that on AC cable.It is therefore of great significance to study the influencing factors of the temperature distribution. The two-dimensional symmetric model is set up by Comsol finite element simulation to calculate the temperature distribution of ±500 kV HVDC XLPE cable in steady state operation, find out ampacity which is suitable for long term operation of cable and study the temperature variation from the aspects of current ampacity and ambient temperature. The simulation results show that the ampacity has a great influence on the temperature distribution. When ambient temperature is higher than 15 ℃,the conductor temperature restricts the ampacity magnitude. While, when the ambient temperature is lower than 15 ℃,the maximum allowable temperature difference of the insulation layer restricts the ampacity magnitude.Finally,the correctness of the simulation is verified through experiment.